Hydraulic pump, fluid motor, or compressor



Nov. 6, 1945. cs. ROESSLER HYDRAULIC PUMP, FLUID MOTOR OR COMPRESSOR Filed May 8, 1943 8 Sheets-Sheet l INVENTOR. Gzorge Eoz sser L I; k V

ATTORNEYS W450 G. RQEssLER" 2,383,644

I HYDRAULIC PUMP, FLUID MOTOR QR COMPRESSOR Filed May 8, 1945 8 Sheets-Sheet 2 INVENTOR. George Qozssler ATTOQNEYS NOV. 6, 1945. RQESSLER 2,388,644

HYDRAULIC PUMP, FLUID MOTOR OR COMPRESSOR Filed May 8, 1943 8 Sheets-Sheet 3 I as I g7 43G 44 n I 7 2| n I :\g. I

IENTOR.

I v eorgz Qozsslzrr I Fig.6 W) I 6 ATTO/QNE Y5 HYDRAULIC PUMP, FLUID MOTOR OR COMPRESSOR Filed May 8, 1943 8 Sheets-Sheet 4 ATTORNEYS Nov. 6, 19 45. ogss g 2,38%,644

HYDRAULIC PUMP, FLUID MOTOR OR COMPRESSOR Filed May 8, 1943 8 Sheets-Sheet 6 I all 70/ 4 h i "HHWI\E@/ 1, umml Ft 13 Fig. M INVENTOR q- 9Poqssler A TTOENEYS Nov. 6, 1945. s. ROESSLER I HYDRAULIC PUMP, FLUID MOTOR' OR COMPRESSOR 8 Sheets-Sheet 7 Filed May 8, 1943 0 l m M G. ROESSLE-R 2,388,644

' Nov. 6, 1945.

7 HYDRAULIC PUMP, FLUID MOTOR OR COMPRESSOR I 8 Sheets-Sheet 8 Filed May 8, 1943 Fig. 23

INV ENT OR. George ROZSSIZF.

ATTORNEYS I have freedom of movement the facility for adjustment Patented Nov. 6, 1945 UNITED STATES PATENT oFricE HYDRAULIC PUMP.

FLUID MOTOR, OR

COMPRESSOR George Roessler, Teaneck, N. J. Application May s, 1943, Serial No. 486,186

- 14 Claims, (01. 103-162) My present invention relates to high speed and I high pressure hydraulic pumps, fluid motors or compressors. It has to do with an improved high presses, automatic machinery, cations, liquefaction of gases, multi-stage compression, variable speed power transmission, remote controls of many types, in'the refrigeration and air conditioning arts, and in marine applications, such as gun turret controls and submarines.

There is at this time a definite and obvious need, in what might be termed the high pressure division of the hydraulic field, for a satisfactory and efllcient high pressure quirements in the aviation branch pointing directly to the adoption of hydraulic transmissions and hydraulic revolution stabilizers, etc., there is a present and urgent need for a satisfactory new pump and fluid motor which has high qualipneumatic applifications as-to strength, mechanical feasibility and simplicity of construction and production. To meet the requirements it is believed that such a pump should be capable of high speed to permit compactness; that it should be ofsuch mechanical construction that it will operate at high speeds for a minimum of 250 hours under pressure loads of 3000 pounds; that it should be free from hydraulic lock and that the construction should of the working parts so that it will be non-heating inoperation and have a low initial power factor. It should have so that when a predetermined and selected pressure output is reached, it will cease to produce further output or consum'e power until the circuit pressure therecally adaptable for use in connection with power pump. With war recontaining a rotor mounted on a shaft having an in has been dissipated by useful work or otherwise has fallen below'the pressure identified with the adjustment. It should have means for making volume adjustments to suit the exact circuit requirements accordingto a prescribed timing. It should have means for quick adjustment from high volume and low pressure, on the one hand. to low volume and high pressure-on the other hand, and such means should be arranged so as to be responsive to regular circuit controls.

It is, therefore, one of the objects of my present invention to provide an'improved high speed variable volume hydraulic pump having all-of automatically maintain the the foregoing features and characteristics which is capable of operating'at high speeds and pressures for long periods of time without overheating; one which is of sturdy, compact and relatively simple construction, containing comparatively few working parts, and one which is capable of being manufactured by mass production methods.

Another object of my invention is to provide an improved pump of the foregoing character which is capable ofvolume adjustment to suit any particular circuit requirements: and one which is capable of quick adjusment from high volume and low pressure to low volume and high pressure. a

Another object sought in the new and improved design embodying my invention is to provide an assembly and operating principle wherein the pressure-making members are opposed or doubleacting, thus splitting the working load and back pressure and placing one half against the other to effect a counterbalance of the pressure. I A further object of the invention is to provide an improved hydraulic pump capable of being set to operate at a given or predetermined speed and pressure output" and which will automatically maintain said speed and pressure output regardless of any variation in the speed of operation of the motor, engine, or other source of motive 1 power unit to which the pump is drivingly conne'cted.

Generally speaking and as shown in the drawings, by way of illustration and not of limitation, the improved high speed and pressure hydraulic pump, fluid motor, or compressor embodying my present invention consists of a housing or casing extension for connection'to a source of power, the rotor including opposed cylinders and sets of pistons therein, a thrust assembly suspended within the housing and shiftable into an angular.

or tilted position, said assembly including a thrust ring or member which is rotatable with said rotor and being operatively connected with said pistons to reciprocate the same upon rotation of the rotor and the thrust ring or member, and a regulating device capable of being set or adjusted to speed and pressure of the pump constant.

The foregoing and other objects and advantages of my'invention will appear from the following description and appended claims when considered in connection with the accompanying drawings forming a part of this specification, wherein like reference characters designate corresponding parts in the several views.

I tiaily along the line 22 In said drawings:

Figure 1 is a perspective view of my improved hydraulic pump, motor or compressor.

Figure 2 is a view similar to Figure 1, partly in section and partly broken away.

Figure 3 is an end elevational view of the pump embodying the invention.

Figure 4 is a side elevaticnal view of my improved pump structure shown in the preceding views.

Figure 5 is an enlarged horizontal sectional view taken substantially along the line 2-4 of Figure 3, looking in the direction of the arrows.

Figure 6 is an enlarged elevational view, partly broken away, of the lower portion of the structure shown in Figure 3.

Figure 7 is an enlarged section taken substantially along the line |-I of Figure 3, looking in the direction of the arrows, and showing the parts in operative pumping position.

Figure 8 is an enlarged fragmentary vertical sectional view taken substantially along the line 2-2 of Figure 9, looking in the direction of the arrows.

Figure 9 is an enlarged of Figure 8, looking in the direction of the arrows and showing the parts in neutral position.

Figure 10 is an enlarged detail vertical section taken substantially along the line ll-il of Figure 9, looking in the direction of the arrows.

Figure 11 is a view similar to Figure 10, showing the parts in different positions.

Figure 12 is an enlarged vertical sectional view taken substantially along the line i2-l2 ,of Figure 4, looking in the direction of the arrows.

Figures 13 and 14 are diagrammatic views illustrating the kinematic system governing the actuating elements of the structure embodying the present invention.

Figure 15 is an enlarged detailed sectional view, partly in elevation, taken substantially along the line i2il of Figure 16, looking in of the arrows.

Figure 16 is a side section, of one of the elevationalview, partly in keepers or cages for maintaining a pair of opposed pistons and one of the ball pins in assembly.

Figure 17 is an enlarged detail sectional view, partly in elevation, of one of the pistons and ball pin assemblies of the invention.

Figure 18 is a fragmentary detail perspective view, partly in section and-partly broken away,

showing somewhat more in detail the structure disclosed in Figures l5, l6 and 17.

Figure 19 is an end elevational view of one of the cylinder shells of the rotor.

Figure 2015 a sectional tially along the line 22-22 of'Figure 19, looking in the direction of the arrows.

Figure 21 is an end elevational view of the other cylinder shell of the rotor.

Figure 22 is a sectional view taken substantially along the line in the direction of the arrows.

Figure 23 is a fragmentary sectional view of a hydraulic pump embodying the invention, similar to that of the preceding views, but showing a modified form of regulating device or mechanism for the thrust bearing assembly; and

Figure 24 is a view similar to Figure showing a further modified form of piston and section taken substanview taken substan- 22-22 of Figure 21 looking 23 but the direction asses lariytol'igures 1to12thereof,tbeimprovedhydraulicpump, fluid motor, or compressor of my present invention comprises, as best seen in Figuresl and3,acompactstructureorunitwhich includes a central housing or casing 2| provided withasupportingbaseorfeetflaandendplates or closures 22 and 22. The housing and end plates support a. rotor assembly shown as a whole at 2|, Figure 5, with which is associated a thrust assembly or thrust bearing assembly shown as a whole at 22. The thrust bearing assembly is supported to permit turning movement about its axisbyme'ansofapairofdiametrlcallyopposed trunnions 22, 22 which are mounted in the central housing 2 i The rotor 22 consists of a pair ofcylinder shells 21 and 22 both of which are mounted, in tandem relation, upon and keyed to a shaft 22 Journaied in the end plates or walls 22 and 22 and which has an extension projecting through and beyond the end plate 22, said extension carrying a key 22 permitting the shaft to be coupled to a suitable source of power, such as an engine or motor (not shown) 1 The cylinder shell 22, hile being keyed to portion 42 of shaft 22 to prevent relative rotation of the shell and shaft, has a snug sliding at on the shaft. Moreover, this shell 22 has a closed or solid end wall 224 and forms a hydraulic cylinder. .A vent 41 through the end wall 221: and the disk valve 21 opens into the pressure port and provides pressure to said cylinder and over the end of the shaft portion 42. Since there are always four pistons on the pressure side which are subiect to operating pressure, there is a tendency for this pressure to break through the seal between the cylinder shell and the valve 21. In other words. the back pressure tends to force the cylinder shell away from the valve and to increase the filament of lubricant between the valve and cylinder shell, in accordance with the viscosity of the lubricant, to an extent which might be considered leakage. By providing a shaft portion 42 of an area which is slightly greater than the combined area of four of the pistons to be described below, a hydraulic diflerential is provided which can be calculated and will provide the correct pressure of the cylinder shell 22 against the valve 21 to assure a seal under any conditions of circuit pressure or viscosity of hydraulic oil. This sealing pressure automatically increases as the circuit pressure increases and any wear on the faces of the disk valve 21 and the cylinder shell 22 is automatically compensated for. A compression spring 22 is provided to obtain the sealing effect at low pressures and before there is enough circuit pressure 'to make the cylinder hydraulically operative.

bly, embodying the present invention.

Referring now to the drawings, and particu- The pressure of this spring becomes a negligible factor almost immediately after starting the pump in operation and this occurs at very low circuit pressures.

Each of the cylinder shells of the rotor is provided with a plurality of bores, eight such bein shown in the present instance for each shell, which provide cylindersfor sixteen reciprocable pistons 2i. One of these pistons is clearly shown in Figure 1'! of the drawings and, as shown, is provided with a spherical socket 2la formed in the inner end of the piston head which defines the inner end of a cylindrical opening or space formed in the piston. The lower or inner end of the piston is provided with an annular flang 2lc and its outer periphery, adjacent the flange, with an annular groove'lid. The piston is provided with a universal type connecting rod 22 .nular pressure seals of whoseinnerendflaisbalishapedtoiltthe sphericalsocket 3la. The opposite end of the connecting or universal rod 32 is enlarged and is cupped to provide a socket 32b. The socket 32b is adapted to engage and form a seat Or bearing for the spherical portion or end of a ball pin 33.

It will be understood that the pistons 3i are ar-.

ranged in pairs and in tandem relation in opposed pairs of cylinders formed in the cylinder shells 21 and 23. v

Each pair of opposed pistons 3| is assembled with a ball pin 33. For this purpose, as shown, see particularly Figure 15, 16 and 18, ,I provide a so-called keeper or cage. which is shown as a wholeat 34. This cage comprises a pair of spaced substantially U-shaped members or yokes 34a which seat in the grooves 3| d or the opposed piston and which embrace'the flanges 3ic formed on the pistons. The yoke members 34:; are held together and in' binding relation with the opposed pistons by means of a plurality of rods or pin 34b,

four such being shown, whose outer ends are flattened or turned down to cause the yoke members to bind the pair of opposed pistons 3| and ball pin 33 together as aunit or assembly.

While I have shown and described the cylinder shells 21 and 23 as each containing eight pistons 3|, it is to be understood that the shells may be formed to contain any desired number or pistons and that either an odd or even number of pistons may be located in each of said shells.

The thrust bearing assembly 23 includes, in addition to its non-rotatable outer ring-like portion, a thrust ring35 which receives and supports the stems or shanks of the ball pins 33, one such ball pin being provided for each pair 01' pistons located in the shells 21 and 23.

Located in suitable sockets in the end plates 22 and 23 are disk valves 33 and 31, respectively. The disk valve 33 has a tubular hub portion 331: which extends through a bearing formed in the end plate 22 and which surrounds a portion or section of the shaft 23. The disk valve 31 is provided with a hub portion which is intemally' threaded to receive a cap screw or bolt 31a providedfor the purpose of holding the valve 31 in proper position with relation to the rotor cylinder shell 23.

Each of the disk valves is provided with two sets oi ports 33 and 33, ports 33 serving as intake ports and ports 39 as discharge ports, there being four such ports in each set, the two sets being separated by means of solid portions 43 which serve to separate the pressure of exhaust from the negative pressure of intake and provide a cut-off between these two at th face of the valve and as tl'iecylinder shells 21 and 23 revolve. The

- yalve ports 33 and 33 register with the cored pas sages 4| and 42 formed in the end plates 22 and 23, which passages are in communication with the cored passages 43 and 43a formed in the central housing 2i adiacent and communicating with the inlet or intake opening 43 on the one hand and the discharge or outlet opening 43 on the other hand, see particularly Figure 5 of. the drawings. As seen in thisilgure, all of the Joints between the casing sections or portions in the region of these passages are sealed by means of suitable anconventio'nal nature, shown at 44.

Since the inner end portion of the intake passage 4| formed in the end plate-22 extends below the shaft 29 and the opposite end portion thereof charge passage 42 located in the end plate 22 ports or slots 33 and-33 formed in the disk valves 33 and 31 must be arranged or located accordingly so that they will register properly with the passages and 42. Thus, the valve 33 has its set of four discharge ports 39 located in the upper half of the valve to register with the passage 42, whereas the set of four intake ports 33 is located in the lower half of the. valve 33. At the opposite end the sets of ports in valve 31 are reversed. The set of four discharge ports 39 islocated in the lower half of valve 31, whereas the set of four inlet or intake ports 33 is located-in the upper half oisaicl valve. The inner adjacent ends of the passages 4i and '42 are not connected but are in communication with one another through the medium of the valves 33 and 3'! and the various pistons 3i.

By providing, as shown, four intake ports or slots 38 and four outlet or discharge ports or slots 39 in each of the disk valves, instead of employing a single continuous intake slot and a single continuous outlet slot, the valve has greater strength than if 'two continuous slots were used. The effect is the same with the two sets of four slots, which, see particularly Figures 10 and ll, are staggered and overlap, so to speak, as if two separate and continuous slots or ports were employed.

Referring particularly to Figure 9, it will be seen that a vent or passageway 37 is provided in the disk valve 31 and communicates with a port or opening I33 through the cylinder shell 28. The portion 43 of the shaft 29, as seen in Figures 7 and 9, and as stated above, has an area which is slightly greater than the combined area of four of the pistons 3i in the cylinder shell 28. The compressionspring 49, is located in a cylindrical recess formed in the shaft portion 43 for the purpose of forcing the cylinder shell against the face of the disk valve 31 to thus provide a sealing efiect at low pressures.

Referring now to.Figure 12 of the drawings it will be seen that the thrust bearing assembly is provided with a split yoke or housing .33, the-two halves of which are held together by screws or bolts 3i.

it will be seen that the split yoke or housing 50 of the thrust bearing assembly is provided-with a located in end plate 23 extends above or over; said\ shaft, and since the inner end portion of the diapair of hardened steel ball races 52 and with a ball bearing assembly 33 with which the thrust ring 35 is in engagement and that the portions or surfaces 34 of the end' plates 22 and 23 provide bearings for the rotor assembly 24-, these bearings being lubricated at points 5 5 by means of lubricant supplied through the lubricating vents 53 from the pressure port, At point 37 there is provided a hydraulic cushion which is fed lubricants by the vent 33 -to provide a counter-balancing force, see

also Figures 10 and 11 which'elearly show thelocation of the lubricating vent 33 and the space or recess where the hydraulic cushion 51 is created. In Figure 9 there is shown a drain orifice 33 communicating vided for the purpose of maintaining a'constant oil level within the basin or lubricant containing reservoir I23 of the pump. Splash lubrication is provided for the internalworking mechanism of my pump, I The oil supply could be introduced through a suitable oil hole provided for that purordinarily the pressure seepage within withan oil drain pipe 59 prothe pump and from the circuit is relied upon to fill the oil basin at the bottom of the housing 2|.

As best seen in Figure 16, each of the ball pins 33 is drilled at $0. This drilled hole 60 is in communication with a pair of lateral orifices or ducts 60a which extend through the ball pin and supply oil collected by the hole "to the surface of the ball which seats in the sockets 32b formed in the inner ends of the connecting rods 32, thus lubricating the contacting surfaces of the ball and the sockets in the opposed connecting rods 32. -The a centrifugal force of rotation of the parts furnishes the pressure.

Referring now particularly to the diagrammatic views in Figures 13 and 14 in which there is illustrated the kinematic system governing the actuating elements of the device, the circular orbit of the pistons is shown at 6|. The focal point of the ball pins 33 is shown at 62 and this focal point describes the are 63 when the thrust assembly 25 and the ball pins are swiveled on the trunnions 26. The focal point 62 is placed somewhat beyond the circular orbit iii of the pistons so that when the angular position of the focal point orbit is projected as shown at H, the orbit becomes elliptical and has both major and minor axes. At the axes the focal points travel above and below the circular orbit of the pistons and the distances above and below said orbit are the same. At intermediate points such as at 65, the orbits cross each other and the focal points of the ball pins together with the ball pins 33 are in exact alignment with the pistons. O

The distance between the focal points as measured along the chord 60 is fixed and invariable. Since, however, the rotation is defined by and confined to an elliptic orbit, when they are at or near the minor axis, the chord 66 is less than the similar chord as measured between the centers of the pistons. The ball pin chord, at or near the major axis, is greater than the piston chord. Therefore, when the ball pins and pistons are rotating on their respective orbits as described, there is a sidewise movement of the ball pins relative to the pistons. The movement of the focal points above and below the circular orbit of the pistons and the relative sidewise movement are maximum at the major and minor axes, but at an intermediate position as shown at 65, the points coincide with the circular orbit of the pistons. These movements can be so calculated that the opening ilb in the piston 3i and the diameter of the connecting rod 32 can be made to provide ,a bearing contact which will drive the thrust ring 35 .at the four places on the orbit as located by the axes. points progress around the orbit to a point midway between the intermediate point and the axis, one set of four bearing contacts give up their driving function to the other set of four bearing contacts and this occurs eight times during one revolution of the parts about the orbit, thus conforming to a mechanical principle which I might term, for convenience, an improved universal joint.

Referring again particularly to Figure '7 of the drawings and with particular reference to the regulating device or mechanism of-my improved pump structure, there is shown a piston 61 which is adapted to have reciprocating movement in bored holes in the central housing 2| and the end plates 22 and 23. The piston'il has a pressure-tight fit in the portion of the bore designated by the reference character 82. The piston I1 is provided with a notch or cut-out portion 2 which is adapted to receive a proiection or lug 10 formed on theyoke memlier ll of the thrust bearing assembly 25. By providing such means, reciprocating movement of the piston '1 will cause movement of the thrust hearing assembly 2! resulting in a change of its angular" position about the trunnions 26. One end of the piston 1 is socketed to receive and support a compression spring ll whose tendency is to'move the thrust bearing assembly to its angular position as shown in Figure 7. provided with a cylinder cavity or chamber 12 which serves to provide hydraulic pressure to the piston 01. Byreferencetol'igures2and8an orifice 12 is provided which connects the cylinder cavity 12 with that the cylinder cavity can be and is supplied with circuit pressure.

.The particular improved type of regulator demy invention in Figure 8. The valve structure, as shown, comprises a body portion H, needle valve II and a compression spring I! which engages at its lower end the valve I! and at its upper end, an adjusting screw and lock nut 11, the spring tending to normally maintain the valve upon its seat ll to close the passage ll from the valve seat. The lower end of the body portion I4 is provided with vents II which communicate with a cored passage II. when the needle valve is on its seat 18 the orifice II is seated but when suflicient hydraulic pressure is exerted in the lower part of the orifice or passage I! to compress th'e' spring Ii, the needle valve is lifted from its seat to permit hydraulic ressure to escape through the vents ll, cored passage 8| and back through the intake port. The escapement orifice thus becomes a. metering or measuring orifice with high pressures serving .40 to compress the spring to a greater extent, lifting the needle valve further away from its sealing position and permitting agreater flow of escapement. When this escapement flow is greater than the incoming flow through the orifice II, the pressure in the cylinder 12 (Figure 7) becomes dissipated and the piston 81 will move toward the left of Figure '1 and into the cylinder cavity.

It will be understood that the thrust assembly 28 swivels freely on its supporting trunnions 2i and that the thrust assembly must be lfeld in an 1 angular position with relation to the axis of the As the focal rotor 24 such, for example, as that shown in F18- ure 7, to produce an effective pumping stroke. It is to be further understood that when the thrust assembly 25 is in a central or neutral position, see Figure 9, there is no pumping stroke and therefore there cannot be any hydraulic output by the pump. Furthermore, when the full energy of hydraulic back pressure as related to the area of eight pistons is applied according to the principles of force resolution and this enersy tends to turn or swivel the thrust assembly 2| m the neutral position, thecalcuiaited tendency for the thrust assembly to return to the neutral position finds its countering force in the hydraulic effort which issues from the cylinder cavity I2 and an overbalance of hydraulic effort is provided to hold the'angular position in accordance with the functioning of the needle valve II of the regulator device.

The piston I has a calculated area which provides a force which is slightly greater than the calculated force of the thrust assembly 2| which tends to return said assembly to the neutral position. When there is no circuit pressure within The end plate 22 is' the cored pressure passage 42 so I assent;

the cored passages, the compression spring 1| moves the thrust assembly 20 to maximum pumping position as seen in Figure "l and when there is circuit pressure the hydraulic eil'ort supplied by the cylinder cavity, 12 is always greater than the force which tends to move the thrust assembly to a neutral position. When, however, the circuit pressure becomes great enough to raise the needle valve oil its seat to the extent which permit the metering off of a fiow equal to or greater than the flow through the inlet passage or orifice 18, then the pressure in the cylinder cavity 12 drops and the thrust assembly '25 moves toward its neutral position (Figure9) thus reducing the hydraulic output to the circuit. As this hydraulic output is thus being reduced, the circuit pressure is likewise being reduced correspondingly and the needle valve 15 is revising the difierential flow through the orifices and the consequent pressure inthe cylinder cavity 12. These reactions follow in rapid succession. Thus, the regulator valve measures the circuit pressure and regulates the hydraulic output of the pump so that it never exceeds, within certain operational limitations, the maximum pressure which has been determined by the strength of the valve spring 18. The strength or power of this spring can be adjusted within a wide range by virtue of the provision of the adjusting screw and lock nut 11.

As seen in Figure '7, the head portion of the pision 61 is provided with a longitudinal slotor groove 82 in its periphery to dispose of the meton effect. Moreover, see Figure 8, a communieating vent or passageway 83 is provided to assure freedom from hydraulic lock which might be caused by pressure seepage past the needle valve 15.

In accordance with my invention Ihave provided means to supp y nd maintain a fllm of lubricant between the adjacent faces'of the cylinder shells 21 and 28 and the valves 36 and 31, 'while at the same time preventing the film from becoming, during rotation of the parts, a so-called pressure break-out. Such means are best shown in Figures 19 to- 22, inclusive, of the drawings. In Figures 19 and 20, the end wall 28a of the pressure cylinder 28 is provided with a a centrally disposed port o opening I05 which communicates with the passage 11, see Figures 7 and 9. The face of the pressure cylinder 28,

as shown, is provided with an annular groove I06- and a series or plurality of intersecting and interconimunicating radial slots or grooves I01. The slots or grooves I01, as shown, terminate at their outer ends at points between and'opposite the approximate centers of the cylinder cavities or piston chambers b. The face of the cylinder shell 28 is also provided with a series of relatively small notches or grooves I08 which are located around the peripheral edge of the cylinder shell face and are diametrically disposed to and spaced from the outer ends or the radial grooves iiii.

The face oi the cylinder shell 21 is provided with a series or plurality of radial grooves or slots I09. similar to the grooves I01 but which, as shown, are somewhat shorter than the grooves I01.

These grooves I09 are located between the cylinders or piston chambers 21b and their outer ends terminate at points between and opposite the approximate centers of said chambers. The race oi the cylinder shell 21 is also provided with a plurality oi relatively small notches or grooves M0, corresponding in number to the slots I09 and being located at the peripheral edge of the face at points diametrically opposite and spaced from the radial slots I09.

.As the cylinder shells or cylinders 21 and 28 0 t rotate over and in contact with the adjacent faces 01' the valves 86 and 31, the grooves I09 and I01 carry the film of oil and wipe it across the adja-- grooves is a neutral pressure. Thus, with one of .the grooves I01 or I00 containing lubricant hav- 20 ing a neutral pressure sweeping, during rotation, after-each pressurized cylinder or piston cavity 21b or 28b, the excess film pressure, which might normally build up and separate the face of the cylinder shell from its seat against the valve, is dissipated and the lubricating grooves or slots on the suction side are automatically provided with enough pressure to insure a lubricating film on that side. By virtue of my improved means or method of lubricating the contacting faces or 0 surfaces referred to above, the lubricant is maintained in circulation and thus a fresh fllm of lubricant will be available at all times. Such method or means reduces friction to a minimum, minimizes wear, and provides for substantially noiseless operation. 1

In Figure 23 of the drawings, I have shown a hydraulic pump structure which is identical in all respects to the improved pump of the preceding views with the exception of the fact that in the present form I'do not employ the automatically operable needle valve regulating device of Figure 8. In lieu thereof I have provided a piston 84 having a notch 85 formed therein and with its skirt portion having a sliding fit at 86 with the bore formed in the central housing 2|, The end plate 23 is provided with a cylinder cavity 81 to provide a recess for the piston to move into. The piston is provided with an internally threaded socket or bore 88 to receive the threaded end 88c of an adjusting screw 89. The screw has a thrust collar 88a and a shank or outer end portion 88b. A keeper plate 00 is adapted to be slipped over the end portion 89b of the shaft and engages the thrust collar 09a to hold the screw in place. The keeper plate is held in-place on the member 23 preferably by means of several screws or bolts 9!, only one being shown. A knurled knob or handle 02 is pushed onto the shank portion 89b and held in place by means of a screw 93. The thrust bearing assembly 25 is provided with a projection or lug 94 which engages the notch ,or cut-out portion 85 of the piston. It will be seen that by turning the handle or knurled knob 02 ineither direction,-the

g5 threaded end we oi the adjusting screw will move or reciprocate the piston 84 in the bore formed in thecentral housing and the end plates. By so adjusting the piston the angular position of the thrust bearing assembly 25 may be changed to increase or decrease the amount ofv pressure and consequent output of the pump. Adjustment is entirely by manual control,-provides selective volume output, and can be changed at any timeduring operation to meet precision requirements. Such change or adjustment will increase or de- 6 I a,sea,e44

crease the powerratio from a theoretically infinite position near the neutral position of the thrust bearing assembly to the minimum at approximately a 20 degree position.

In Figure 24 I have shown a further modified form of hydraulic pump embodying my invention. In this form of the invention I have provided a piston shown as a wholeat'li which, at

its head portion, is substantially like the piston- 94 of Figure 23. The left end portion oi! the pis- 10 ton 95, as viewed in Figure 24, comprises, in effect, a dashpot 9), the head II and the dashpot portion 95b of the piston being interconnected by a central portion 95a which provides, in effect, an integral connecting rod for these portions. The piston at about its central point is provided with a notch or cut-out portion 99 to receive a projection or lug I93 formed on the thrust hearing assembly 25. The dashpot portion or end section 95b of the piston has a pressure-tight sliding fit with the bearing portion 91 formed in the central housing 2| and beyond this portion of the piston the end plate 23 is provided with a cylinder cavity 99, similar to the cavities 12 and 91 of the preceding forms of my invention.

The end plate 22 is provided with a cap bore 99 to receive a pipeline or pilot line I". The bore 99 communicates with the head of the piston 95. The end plate 23 is likewise provided with a tapped bore lill which communicates with the cylinder cavity 99 and to which is connected a pipeline or pilot line 192. It will be understood that the device as constructed in accordance with the present form of my invention may operate as a two-stage pump, having high volume-low pressure for one stage and high pressure-low volume for the other stage. These stages can be automatically selected by a suitable valve arrangement in the circuit. In the present form the orifice or passage 19 of the form of my invention shown in Figures 1 to 18, inclusive, and the automatic pressure regulator of Figure 8, are not used. The end portion 95b of the piston 95 may be designed, if desired, so as to serve as a dashpot for cushioning any hammering effect which might occur at the end of the piston stroke. With the exception of the exclusion of the orifice I3 and the automatic pressure regulater, as best seen in Figure 8, and the redesigned piston structure 95, the pump of Figure 24 is substantially identical with that shown in Figures 1 to 18, inclusive.

The improved pump in its several forms as described above, including its principle of operation, its mechanical movements, elements, devices and assemblies, can be used as a fluid motor by connecting it to a pressure circuit and it will rotate in either direction in accordance with the direction of flow of the circuit. Such a fluid motor can be regulated as to its revolutions per minute by throttling the flow or, in other words, by metering the flow of fluid to the motor. Moreover, by the application of pressure and flow, the

pump of my invention can be used as an air motor and regulated as to pressure and output as desired.

Pumps made in accordance with my invention can be manufactured from various materials such as those which are non-corrosive, rust-proof and acid-resistant and can be used for pumpin any liquids which it appears desirable to pump. In'addition, by adding a lubricating circuit, the pump can be used for the compressing of gases. Thus, it will be seen that m improved pump is adapted for various and diversified uses.

- 'of their suction stroke.

It is believed that the failure in operation of previously known pumps has been due largely to misconceptions and errors in design particularly with respect to the fluid circuits of these pumps. These errors in design, the use of faulty and improper accessories, the presence of hydraulic lock, vibration and chatter were reflected in the pump, since in an assembly or group of mechanical apparatus or units, the pump is the unit-which receives the application of the power in the form of shock or hydraulic hammer. With my improved pump structure including the automatic pressure-limiting device, this shock or hammer factor is substantially reduced. if not entirely eliminated. Furthermore, the variable volume requirement of any given cycle of circuit operation will be translated precisely to the power source instead of building up a pressure to break through a relief valve which must always be adjusted to exceed the maximum pressure requirement. In a pump structure provided with a relief valve, the maximum power requirement occurs when the circuit is idle.

Operation The operation of my improved hydraulic pump as shown in Figures 1 to 18, inclusive, of the drawings is substantially as follows:

Let us assume that the pump structure is to be used to deliver a constant supply of fluid, such as oil, under pressure to one or a plurality of fluid transmissions, or the like, or for any other use wherein it is desirable to maintain a constant supply or volume and 'a given pressure of oil or other fluid. Let us assume also that the exposed end of the shaft 29 is keyed or otherwise drivingly connected to asource of motive power, such as an internal combustion en ine, electric motor, or the like (not shown).

The working parts of the hydraulic pump. as shown in Figure '7, are in their idle position prior to the application of power to the shaft 29. When power is applied to the shaft 29 the thrust assembly 25 is held in its tilted or angular position by virtue of the force of the spring II which maintains the piston 21 to the right of Figure 7, the notch 99 in the piston holding the lug or projection 19 of the thrust assembly in the position shown in this figure. Rotation of the shaft will likewise cause rotation of the rotor 24 and the simultaneous rotation of the thrust ring 35 and ball pins 33 of the thrust assembly. It will be understood that the rotatable parts of the thrust assembly will rotate as a unit with the rotor and by reason of the fact that each pair of opposed pistons -ll of the rotor, through the connecting rods 32, is directly connected with a ball pin 92 by means of the cage or keeper :4, the pistons will be caused to reciprocate in their respective cylinders 21 and 28 as the rotor revolves.

There are eight of the pistons 9| located in each of the cylinder shells 21 and 29. Each pair of opposed pistons reciprocates or operates as a unit so that while piston II in cylinder shell 21 is performing its suction stroke, the other piston ii of the pair located in cylinder shell 28 is performing its discharge stroke. The pairs of opposed pistons follow each other in action and operation in rapid succession and continuously. There are always four pistons in one of the cylinder shells operating at various stages of their pressure stroke and four opposed pistons in the other cylinder shell operating at various stages It will be understood that and 4| and alsothrough the intake ports 30 in each 01 the disk valves 36 and 31. At the same time that this action is taking place other pistons in each oi the cylinder shells 21 and 28 are performing their discharge strokes to force the oil or other fluid through the ports 39 in both of the disk valves 36 and 31 and discharge it through the cored passages 42 and 43 and the discharge opening .46 located in the opposite side of the casing or housing. It will be understood that the pressure sides of the rotor are catawampous.

The disk valves 38 and 31 remain stationary during the operation of the pump-and their separate sets of tour intake and four exhaust ports 33 and 33, respectively, remain stationary whereas the various pistons during their rotation alternate in performing their intake and discharge strokes.

As the rotor 24 and the thrust ring 35 and ball pins 33 rotate and cause the pistons 3| to build up pressure, the tendency of the thrust assembly is to assume or move toward its vertical position as shown in Figure 9. This is resisted. however, by the oil pressure in the cylinder cavity 12 at the end 01' piston 61. This cylinder cavity is in direct communication through an orifice or passageway 13 (see Figures 2 and 8) with the oil in the cored discharge passage 42.

So as to be able to adjust the-hydraulic pump in such a manner as to regulate its pressure output, I have provided the regulator device previously described which includes the springpressed needle valve I and associated parts, as best seen in Figure 8. The valve spring 16 may be adjusted to apply any desired force to maintain the needle valve on its seat 18 through the medium of the adjustment screw and nut 11 located at the top of the valve body 14. For ex- .ample, if it is desirable to discharge oil through the discharge opening 46 at a pressure of say 3000 pounds per square inch and to maintain this pressure, the spring 18 is adjusted so as to cause the needle valve 15 to remain upon its seat against the action or the pressure within the cylinder cavity it for all pressures up to 3000 pounds p. s. i. If, however, the pressure in the discharge passages 42 exceeds 3000 pounds, p. s.- 1.. the valve i5 is forced or lifted from its seat Y againstv the action of thespring I6, which permits the escape of pressure through the vents 80 and cored passage Bi back to the intake passage 4 i. When this escapement through the metering needle valve 15 exceeds the flow of fluid through the oriflce 13, the pressure in the cylinder cavity is reduced permitting the thrust assembly 25 to move gradually in the direction toward its vertical position against the action of spring H to slow down the pumpin action and allow the pressure to be reduced to the predetermined maximum oi! 3000 pounds per square inch for which the regulating devioehas been adjusted.

,It will be understood that the needle valve 15 meters the flow of fluid, that the flow through the valve i5 and the oriilce 18 is on a diiferential basis and that the pressure, therefore, in the cylinder cavity 12 is constantly rising and falling to accomplish a precise regulation of the pump. As a result oi'the action of the needle valve the force tending to drive the thrust assembly 23 to neutral or vertical position and the force of the piston 81 are being constantly regulated hydraulically to produce a volume which, in turn, will hold to a norm of pressure as determined by the needle valve 15.

It will be understood that movement of the thrust assembly from its degree angular-position toward its inactive or neutral vertical position gradually reduces the pressure output of the pump. The tendency of the spring H is to move the-thrust assembly 25 toward its angular or working position at all times and serves to counteract the tendency of the thrust assembly to move or swing back, due to the back pressure on the pistons, toward its vertical or inactive position. To assist the spring ii to counteract this tendency on the part of the assembly 25, the pressure in the cylinder cavity 12 acts upon the piston 61 to force it toward the right of Figure 7 and maintain the thrust assembly .inits proper angular or pumping position in accordance with the degree of pressure for which the pump is adjusted as determined by the pressure or iorce exerted on the needle valve it by its spring 16.

After the pressure in the discharge passages 43 has been reduced to 3000 pounds p. s. i. or less, the force or power of the spring it will return the valve ii to its seat, close passage i8 and allow the pressure in cylinder cavity 12 to build up to normal, for example 3000 pounds p. s. i.

The hydraulic pump of my invention is designed to deliver a steady or constant output or flow o1 fluid at a given or. predetermined pressure regardless of the speed at which the engine,

. motor, or the like which drives it, is operatlimit pump is used with a safety device in such a .also be done when the motor ing'. The regulator valve 75 measures the circuit. pressure and regulates the hydraulic out- Put of the pump so that it never exceeds, within certain operational limitations, a maximum pressure as determined by the strength of the valve spring 18.

Combinations of my improved pump and fluid motor can be used for many new and useful purposes. l

The pump and fluid motor can-becombined into a unit to be used as a speed variator wherein the pump is driven at constant R. P. M. and

the fluid motor is metered to produce a diflerent R. P. M. to suit a given requirement; or wherein the angle of the thrust assemblyof the pump or of the fluid motor, or both, may be adjusted to obtain the described speed change. This may tion with relation to the pump. a

A combination may be used wherein a pressure fluid motor as a torque way that the speed of the fluid motor will slow down or even come to a stop when torque loads occur.

A pump and fluid motor combination may be used to produce the greatest R. P. M.-of output with a constant power input when the torsional load is extremely variable.

Moreover, the combination maybe used as a revolution stabilizer for obtaining a constant output of R. P. M. from a. source of power which is highly variable as to'R. P. M.

Many other combinations may be used within the scope of my present invention.

is a remote loca- It is to be understood that the type or me-' chanical structure herein described, particularly as it applies to hydraulic pumps and the motors,

which discloses any inherent weakness and the limitations of pressure created are restricted only by the strength of the materials used. The present pump will give a lasting performance for the reason that the wearing parts are reduced to a minimum, the bearing surfaces are ample and because the thrust of the hydraulic load is carried directly by a ball bearing assembly.

For the foregoing reasons and because full use is made of pressure lubrication, the improved pump structure of the present invention can be operated at speeds which are substantially higher than could be obtained from previously known pumps and because of the fact that the pump casing or housing is provided with cored passageways of relatively large area, there is a minimum tendency to produce or generate heat during pressure operation.

Having thus described my invention, what I claim is:

l.- A hydraulic pinnp comprising a housin having intake and discharge openings, 9. rotatable shaft journaled in said housing, a rotor including opposed cylinder shells and sets of coaxial opposed pistons rotatable with said shaft, a thrust bearing assembly suspended within said casing having a portion rotatable with said rotor, means for operatively connecting said assembly to said pistons for reciprocating the same, said thrust bearing assembly being capable of tilting movement about its points of suspension between a vertical position and an angular position, spring means for normally maintaining said thrust hearing assembly in its angular position, and pressure means for controlling the angular movement oi! said usembly.

2. A hydraulic pump or the axially rotatable type comprising a housing having intake and discharge openings, a rotatable shaft journaled in said housing, a rotor including Opp sed cylinder shells and sets of coaxial opposed" pistons rotatable with said shalt, a thrust hearing assembly suspended within said casing having a portion rotatable with said rotor, means for operatively connecting said assembly to said pistons for reciprocating the same, said thrust bearing assembly being capable of tilting movement about its points oi suspension between a vertical position and an angular position. spring means for normally urging s'aid thrust bearing assemblytoward angular position, and metering valve means in operative communication with the assembly for automatically controlling the angular movement of said assembly whereby to govern thespeed and pressure output or said hydraulic pump. a

3. A hydraulic pump comprising a closed housing having intake and discharge openings, a rotatable shalt journaled in said housing, a rotor including opposed sets of coaxial reciprocable pistons rotatable with said shalt, disk valves having ports formed therein located in opposite walls or the housing and .cooperable with said pistons. type comprising a Within the housing 77 discharge openings,

athrultassemblysuspended "surrounding saidrotor and having members ro\ tatable with said rotor, certain of said members being associated with said pistons for reciprocating the same, said thrust assembly as a whole being automatically shiitable about its points of suspension between a vertical position within the housing and an angular position 01' approximately 20 degrees, and automatic means including said thrust assembly for regulating the out put of said pump.

4. A hydraulic pump comprising a housing having intake and discharge openings, a rotatable shaft journaled in said housing and having a portion projecting outwardly through one of said walls for connection to a source of power, a rotor including opposed cylinder shells and sets of coaxial opposed pistons rotatable with said shaft. a thrust bearing assembly suspended within said housing having parts thereof rotatable with said rotor and operatively connected to said pistons for reciprocating the same, said thrust hearing assembly being capable of tilting movement about its points of suspension between a vertical position and an angular position, spring means for normally maintaining said thrust bearing assembly in its angular position, pressure means for controlling the angular movement of said assembly, and adjustable fluid metering means for relieving the pressure within said pump whereby to maintain the pressure output of the pump constant.

5. A hydraulic pump comprising a housing having intake and discharge openings, a' rotatable shalt journaled in said housing, a rotor including opposed cylinder shells and sets or axially aligned opposed pistons rotatable with said shaft. a thrust bearingassembly suspended within said casing having a portion rotatable with said rotor and operatively connected to said pistons for reciprocating the same, said thrust bearing assembly being capable of tilting movement about its points of suspension between a vertical position and an angular position, spring means for normally maintaining said thrust bearing assembly in its angular position, pressure means for controlling the angular movement of said assembly, and a fluid metering needle valve for relieving .the pressure within said pump when it exceeds a predetermined amount whereby to maintain the pressure output or the pump constant.

6. A hydraulic pump of the axially rotatable type comprising a housing having intake and discharge openings, a rotatable shalt lournaled in said housing, a rotor including opposed cylinder shells and sets of opposed pistons rotatable with said shaft, a thrust bearing assembly suspended within said casin including a thrust ring rotatable with said rotor and having means operatively connected to said pistons for reciprocating the same, said thrust bearing assembly being capable of tilting movement about its points 0! suspension between a vertical position and an angular position, a spring-pressed plunger for normally maintaining said thrust bearing assembly in an angular position, a pressure chamber associated with said spring-pressed plunger for resisting the movement of said assembly i'rom angular position toward vertical position, and metering means including a needle valve for relieving the pressure in said chamber at'predetermined times whereby to maintain the pressure output of the pump constant.

'7. A hydraulic pump of the axially rotatable housing having intake and a rotatable shaft iournaled assessein said housing, a rotor including opposed cyl inder shells and sets of opposed pistons rotatable with said shaft, valves with which said cylinder shells and pistons cooperate, a thrust bearing assembly suspended within said casing having parts rotatable with said rotor, certain said parts being operatively connected to said pistons for reciprocating the same, said thmst'bearing assembly being capable of tilting movement about its points of suspension between a vertical position and an angular position, a spring-pressed plunger for normally maintaining said thrust bearing assembly in an angular position, a pressure chamber associated with said spring-pressed plunger for resisting the movement of said assembly from angular position toward vertical position, and a manually adjustable regulator including a needle valve for automatically relieving the pressure in said chamber at predetermined times whereby to reduce the pump pressure when it exceeds a predetermined limit.

8. A hydraulic pump comprising a housing having intake and dis'charge openings, a rotatable shaft iournaled in said housing, a rotor including opposed cylinder shells and pairs of axiall aligned opposed pistons rotatable with said shaft, valve means associated with said cylinders, a thrust bearing assembly suspended within said casing having parts thereof rotatable with said rotor and operativeLv connected to said pistons for reciprocating the same, said thrust bearing assembly being capable of tilting movement about its points of suspension between a vertical position and an angular position, and means for normally maintaining said assembly in its angular position but permitting movement thereof toward vertical position when the pressurein the pump exceeds a predetermined amount.

9. A hydraulic pump of the axially rotatable type comprising a housing having end plates, a rotatable shaft journaled in said end plates, a rotor including opposed sets of reciprocable pistons rotatable with said shaft, the pistons of each set being arranged .in axial alignment with one another, valves located in the end plates and cooperable with said pistons, trunnions located at diametrically opposite points in the housing, and a thrust assembly carried .by said trunnions surrounding said rotor and having parts thereof ro tatable with the rotor and operatively associated with said pistons, said thrust assembly being movable between a vertical position within the ing a fluid actuated piston having a portion engaging said assembly for tilting the same, said housing having a cylinder cavity located behind said piston, one end of said piston cooperating ,with said cylinder cavity and together providing a dashpot for cushioning the piston at the end of its stroke.

housing and an angular position whereby to cause reciprocation of said pistons upon rotation of said rotor, each of said valves having a series of intake and a separate series of discharge ports whereby upon rotation and reciprocation of said pistons certain thereof of both sets draw in fluid from the induction side of the pump through the intake ports while others thereof of both sets are simultaneously discharging fluid through the discharge ports to the discharge side of said pump.

10. A reversible hydraulic pump comprising a housing having intake and discharge openings, a rotatable shaft .iournaled in saidhousing, a rotor including opposed cylinder shells and opposed pairs of pistons rotatable with said shaft, a thrust bearing assembly suspended within said casing I having rotatable parts operatively connected to said pistons for reciprocating the same, said thrust bearing assembly being capable of tilting movement about its points of suspension between a vertical position and an angular position, and

with said pistons, said thrust assembly being movable between a vertical position within the housing and an angular position whereby to cause reciprocation of said pistons upon rotation of said rotor, and means at the forward end of said shaft for applying pressure to the cylinder at said shaft end to maintain said cylinder in intimate contact with the adjacent valve.

12. A hydraulic pump comprising a closed housing having intake and discharge openings, a rotatable shaft .iournaled in said housing and having a portion projecting outwardly through one of the walls for connection to a source of power, a rotor including spaced bylinders and opposed sets of reciproca'ble pistons rotatable with said shaft, disk valves having ports formed therein located in opposite walls of the housing and cooperable with said pistons, a thrust assembly suspended within the housing surrounding said rotor and having members thereof rotatable with said rotor, said thrust assembly having means associated with said pistons for reciprocating the same, said thrust assembly as a whole being automatically shiftable about its points of suspension between 2. vertical position within the housing and an angular position, means for automatically maintaining said cylinders in intimate contact with said disk valves, and means for maintaining drifting films of lubricant between the adjacent faces of the cylinders and the disk valves.

13. A reversible hydraulic pump of the axially rotatable type comprising a housing, having intake and discharge openings, a rotatable shaft located within the housing, a rotor including a pair of opposed spaced cylinders journaled in bearings formed in opposite walls of said hous-.

naled at one of its ends in a wall of said housing means for maintaining said thrust bearing assembly in angular position, said means comprisand having its opposite end .iournaled in said walled cylinder, disk valves located in the housing walls and cooperating with the outer adjacent ends of said cylinders, a thrust bearing assembly suspended within said housing and having a ring rotatable with said rotor, means operatively connecting said ring and said pairs of pistons for reciprocating the Iattensaid thrust hearing assembly being capable of tilting movement about its points of suspension between a vertical position and an angular position to cause reciprocation of said pistons upon rotation of said rotor,

means for normally maintaining said assembly in its angular position. means for automatically controlling the angular movement ,oi' said thrust and discharge openinsl. a rotatable shaft located within the housing. a rotorincluding a pair of opposed spaced cylinders ioumaled in bearings formed in opposite walls oi said housing. one of said cylinders having openends and the other of said cylinders having a centrally disposed wall at one end thereof, a plurality of pairs of opposed and articulated pistons reciprocably' mounted in said cylinders, said open ended y inder being fixed to said shaft and said other cylinder having a sliding ilt on said shai't but rotatable therewith. said shalt being journalcd at one of its ends in a wall of said housing and having its opposite end iournaled in said walled cylinder, disk valves located in the housing walls and cooperating with the outer adjacent ends of said cylinders, Y a thrust bearing assembly suspended within saidhousing and having a ring rotatable with said rotor, means operatively connecting said ring and said pairs of pistons for reciprocating the latter,

said thrust bearing assembly .being capable oi tilting movement about its points of suspension between a vertical position and angular position to cause reciprocation of said pistons upon rotation of said rotor, means for normally maintain- 1158 said assembly in its angular position, means for automatically controlling the angular movement oi said thrust bearing assembly whereby to govern the speed and pressure output of said pump, and mechanical and hydraulic pressure means between the central wall or said cylinder and the adjacent end oi! said shaft for maintaining the outer iace of said cylinder in intimate contact with the face of the adjacent disk valve.

GmRGE ROESSLER 

